Control of the charging procedure is a crucial aspect of blast furnace operation. Appropriate charging is required for best possible furnace performance, e.g. as regards gas flow and chemical reactions inside the furnace. Typical charging requirements include among others: charging the correct weight of each raw material, keeping the proper order of raw materials and achieving the desired stock-line profile. A related crucial aspect is proper burdening, i.e. determining the required weight of each raw material, in order to ensure proper burden composition for a desired chemistry of hot metal and slag.
In modern plants, the blast furnace is fed with raw materials by means of an automated material feeding installation comprising a stockhouse with automatic weighing equipment and an associated automatic conveyor. In the stockhouse, batches of one or more raw materials (ore, pellets, sinter, coke, flux, etc.) are weighed and transferred to the automated conveyor, e.g. a conveyor belt or skip car arrangement. The conveyor transports the batches to the furnace top, where they are received in a hopper of a top-charging installation. Modern blast furnaces also usually comprise an automated top-charging installation, for example according to the widespread BELL LESS TOP™ principle, which typically includes a rotatable and pivotable chute to allow precise distribution of material on the stock-line according to a desired profile.
Such automated feeding and top-charging installations are controlled by dedicated or common process control(s), which in turn is/are typically operated by means of a computer system serving as human-machine-interface (HMI).
In known systems for computer-assisted control of the blast furnace charging procedure, the operator can program a charging cycle by defining a sequence of batches to be fed from the stockhouse and charged into the furnace. The batches are defined by setting the type and quantity, usually dry weight, of the raw materials to be contained in each batch in the HMI in accordance with a previous manual or computerized burdening calculation. A known system also allows configuring the settings of the top charging installation for each batch via the HMI.